1. Field of the Invention
The invention is directed to an improved fuel injection valve for internal combustion engines.
2. Description of the Prior Art
One fuel injection valve known for instance from German patent disclosure DE 199 41 930 A1 has a housing that includes a first and a second body; the first body is embodied as a valve holding body, and the second body is embodied as a valve body. Both bodies have a contact face with which they rest on one another, either directly or with the interposition of a shim. To brace the valve holding body against the valve body, a screw sleeve is provided, which surrounds both the valve body and the valve holding body and optionally also the shim in the region of the contact faces. The screw sleeve has a female thread, with which it engages a male thread embodied on the valve holding body. A pressure face is also embodied on the screw sleeve, and with it the screw sleeve rests on a contact face of the second body, or in other words of the valve body. The screw sleeve is embodied essentially cylindrically, and screwing it into the male thread of the valve holding body generates an axial force by which the valve holding body is pressed against the valve body.
To introduce a torque into the screw sleeve, a hexagon is created by grinding on its end toward the combustion chamber, so that the turning tool, such as an open-end wrench, can engage the faces of this hexagon in order to exert a suitable torque on the screw sleeve. However, the torque is introduced only via individual introduction lines, each with different torques. At relatively high torques, considerable torsion on the screw sleeve may occur under some circumstances, causing fluctuations in the torque at the thread and thus also fluctuations in the axial force with which the first body is pressed against the second body. Since in many fuel injection valves, high fuel pressure is carried through a conduit that penetrates the contact faces, leaks at the contact faces are consequently possible.